It’s defined in default.css. If you want to change it, create a child theme (search on this site for instructions), copy over the _inc/css folder structure, edit the appropriate elements (div#message if I recall correctly) in default.css and you’re good to go.

You may find the Firebug addon for Firefox extremely useful for tracking down and playing with stuff like this, if you don’t already use it.

Ok so Firebug is awesome and I’m sure now that I can track down the location for the notification title. Now my question is this, how would I switch the widget title for notifications from one color to another when there are new notifications.

So I would have the same color (lets say gray) as all other widget titles but then when there’s a new message or request, the color shows as something else. I’m guessing this needs more than just CSS?

Make a copy of the bp_adminbar_notifications_menu() function (located in /buddypress/bp-core/bp-core-adminbar.php) and add a check to see if there are any notifications to the main list item, if there are, output a CSS class for the list item.

You’ll need to override the default notifications menu in the BuddyBar.